Parvesh Chaudhry

Bridging endometrial receptivity and implantation: network of hormones, cytokines, and growth factors

The prerequisite of successful implantation depends on achieving the appropriate embryo development to the blastocyst stage and at the same time the development of an endometrium that is receptive to the embryo. Implantation is a very intricate process, which is controlled by a number of complex molecules like hormones, cytokines, and growth factors and their cross talk. A network of these molecules plays a crucial role in preparing receptive endometrium and blastocyst. Furthermore, timely regulation of the expression of embryonic and maternal endometrial growth factors and cytokines plays a major role in determining the fate of embryo. Most of the existing data comes from animal studies due to ethical issues. In this study, we comprehend the data from both animal models and humans for better understanding of implantation and positive outcomes of pregnancy. The purpose of this review is to describe the potential roles of embryonic and uterine factors in implantation process such as prostaglandins, cyclooxygenases, leukemia inhibitory factor, interleukin (IL) 6, IL11, transforming growth factor-β, IGF, activins, NODAL, epidermal growth factor (EGF), and heparin binding-EGF. Understanding the function of these players will help us to address the reasons of implantation failure and infertility.

Resistance to chemotherapy and hormone therapy in endometrial cancer

Endometrial cancer is the most common gynecological malignancy in developed countries and represents the eighth leading cause of cancer related death in women. The growing incidence of endometrial cancer leads scientists and oncologists to identify effective preventive measures and also molecular markers for diagnosis and prognosis. Chemotherapy and hormone therapy is the mainstay treatment option for advanced and recurrent endometrial cancer and response to therapy is one of the most important factor which favors prognosis and overall survival. In recent years, there have been major advances in the treatment of patients with endometrial cancer. Despite advances made in the treatment of this cancer, the overall survival of patients has not significantly improved because considerable number of patients harbor tumor refractory to these therapies and the majority of the initially responsive tumors become refractory to treatments. Therefore, determination of sensitivity/resistance is becoming increasingly important for individualization of endometrial cancer therapy. The aim of this review is to present the existing knowledge about the molecular markers that could play a crucial role in determining resistance to chemo- and hormone therapy. Extensive literature search for the cell signaling pathways and factors responsible for chemoresistance have been performed and reviewed. Several recent studies suggest that deregulations in the apoptotic pathways (such as p53, Fas/FasL, Bcl-2 family proteins, inhibitor of apoptosis proteins), survival pathways (PI3K/AKT, MAPK), hormone receptor signaling pathways (progesterone receptor), Cyclooxygenase-2 and Her-2 are considered as key factors involved in the onset and maintenance of therapeutic resistance, suggesting that resistance is a multi-factorial phenomenon.

Prostate Apoptosis Response 4 (Par-4), a Novel Substrate of Caspase-3 during Apoptosis Activation

ABSTRACT Prostate apoptosis response 4 (Par-4) is a ubiquitously expressed proapoptotic tumor suppressor protein. Here, we show for the first time, that Par-4 is a novel substrate of caspase-3 during apoptosis. We found that Par-4 is cleaved during cisplatin-induced apoptosis in human normal and cancer cell lines. Par-4 cleavage generates a C-terminal fragment of ∼25 kDa, and the cleavage of Par-4 is completely inhibited by a caspase-3 inhibitor, suggesting that caspase-3 is directly involved in the cleavage of Par-4. Caspase-3-deficient MCF-7 cells do not show Par-4 cleavage in response to cisplatin treatment, and restoration of caspase-3 in MCF-7 cells produces a decrease in Par-4 levels, with the appearance of a cleaved fragment. Additionally, knockdown of Par-4 reduces caspase-3 activation and apoptosis induction. Site-directed mutagenesis reveals that Par-4 cleavage by caspase-3 occurs at an unconventional site, EEPD131↓G. Interestingly, overexpression of wild-type Par-4 but not the Par-4 D131A mutant sensitizes cells to cisplatin-induced apoptosis. Upon caspase-3 cleavage, the cleaved fragment of Par-4 accumulates in the nucleus and displays increased apoptotic activity. Overexpression of the cleaved fragment of Par-4 inhibits IκBα phosphorylation and blocks NF-κB nuclear translocation. We have identified a novel specific caspase-3 cleavage site in Par-4, and the cleaved fragment of Par-4 retains proapoptotic activity.

Resveratrol Inhibits Cisplatin-Induced Epithelial-to-Mesenchymal Transition in Ovarian Cancer Cell Lines

Background Many patients diagnosed with ovarian cancer experience recurrence and metastasis, two aspects that will often cause their demise. Epithelial-to-mesenchymal transition (EMT) is a key process involved in cancer progression. With increasing evidence linking Cisplatin and EMT, we wanted to identify a compound able to counter EMT progression when cancer cells are treated with Cisplatin. Methodology/Principal Findings Cell death was evaluated by cytometry with Annexin V/PI staining in A2780 and A2780CP cells. Ovarian cancer cell lines were treated with Cisplatin (24 h, 10 µM) and different concentrations of Resveratrol to evaluate its effect on Cisplatin-induced EMT using Western Blot and RT-PCR analysis. Morphological studies and wound healing assay to evaluate cell motility were performed using 72 h Cisplatin treatment with A2780 and A2780CP cells. Densitometry was done on Western Blot and PCR results, and statistical significance was determined using One-Way ANOVA followed by Tukey post-hoc test. Our results show that Cisplatin induced EMT-associated morphological changes in the A2780 ovarian cancer cell line and to a lesser extent in its Cisplatin-resistant counterpart A2780CP. Resveratrol caused cell death in A2780 and A2780CP cell lines in an apoptotic-independent manner. Resveratrol inhibited Cisplatin-induced Snail expression by reducing the Erk pathway activation, reverted morphological changes induced by Cisplatin and decreased cell migration. Conclusions These results indicate that Resveratrol has interesting potential to prevent Cisplatin-induced EMT in ovarian cancer cells. By increasing cell death, it also represents an inviting approach as adjuvant therapy to be used with chemotherapy. Using Erk pathway inhibitors could also prove helpful in ovarian cancer treatment to reduce the risk of metastasis.

Cisplatin-induced caspase activation mediates PTEN cleavage in ovarian cancer cells: a potential mechanism of chemoresistance

BackgroundThe phosphatase and tensin homolog deleted on chromosome 10 (PTEN) tumor suppressor protein is a central negative regulator of the PI3K/AKT signaling cascade and suppresses cell survival as well as cell proliferation. PTEN is found to be either inactivated or mutated in various human malignancies. In the present study, we have investigated the regulation of PTEN during cisplatin induced apoptosis in A2780, A270-CP (cisplatin resistant), OVCAR-3 and SKOV3 ovarian cancer cell lines.MethodsCells were treated with 10μM of cisplatin for 24h. Transcript and protein levels were analysed by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) and western blotting, respectively. Immunofluorescence microscopy was used to assess the intracellular localization of PTEN. Proteasome inhibitor and various caspases inhibitors were used to find the mechanism of PTEN degradation.ResultsPTEN protein levels were found to be decreased significantly in A2780 cells; however, there was no change in PTEN protein levels in A2780-CP, OVCAR-3 and SKOV3 cells with cisplatin treatment. The decrease in PTEN protein was accompanied with an increase in the levels of AKT phosphorylation (pAKT) in A2780 cells and a decrease of BCL-2. Cisplatin treatment induced the activation/cleavage of caspase-3, -6, -7, -8, -9 in all cell lines tested in this study except the resistant variant A2780-CP cells. In A2780 cells, restoration of PTEN levels was achieved upon pre-treatment with Z-DEVD-FMK (broad range caspases inhibitor) and not with MG132 (proteasome inhibitor) and by overexpression of BCL-2, suggesting that caspases and BCL-2 are involved in the decrease of PTEN protein levels in A2780 cells.ConclusionThe decrease in pro-apoptotic PTEN protein levels and increase in survival factor pAKT in A2780 ovarian cancer cells suggest that cisplatin treatment could further exacerbate drug resistance in A2780 ovarian cancer cells.

Transforming Growth Factor-Beta Regulates Proliferation and Invasion of Rat Placental Cell Lines

Implantation of an embryo in the endometrium is a critical step for continuation of pregnancy, and implantation failure is a major cause of infertility. In rats, the implantation process involves invasion of the endometrial epithelial lining by the trophoblastic cells in order to reach the underlying stromal cells. Transforming growth factor beta (TGFB) is a multifunctional cytokine that regulates proliferation, differentiation, and invasiveness of multiple cell lineages. We used rat HRP-1 and RCHO-1 placental cell lines to perform this study. HRP-1 cells were derived from midgestation chorioallantoic placental explants of the outbred Holtzman rat, whereas RCHO-1 cells were established from a rat choriocarcinoma. MTT proliferation assays revealed that each TGFB isoform decreased HRP-1 cell growth in a dose-dependent manner, whereas RCHO-1 cells were resistant to the growth-suppressive effect of TGFB1 and TGFB3. Only TGFB2 reduced RCHO-1 cell proliferation. Activation of ERK, MAPK14 (p38 MAPK), or SMAD pathways is known to play a role in cell proliferation, and we found that TGFB activates these pathways in both HRP-1 and RCHO-1 cells in an isoform-specific manner. MTT proliferation assays revealed that ERK pathway is partially implicated in TGFB3-reduced HRP-1 cell proliferation. Hoechst nuclear staining and caspase-3 cleavage demonstrated that TGFB isoforms failed to induce apoptosis in both cell lines. Matrigel invasion assays showed that both HRP-1 and RCHO-1 cells exhibit intrinsic invasive ability under untreated conditions. The capacity of HRP-1 cells to invade the Matrigel was selectively increased by TGFB2 and TGFB3, whereas all TGFB isoforms could increase the invasiveness of RCHO-1 cells. These important functional studies progressively reveal a key role for TGFB in regulating proliferation and invasiveness of placental cells.

XIAP gene expression and function is regulated by autocrine and paracrine TGF-β signaling

BackgroundX-linked inhibitor of apoptosis protein (XIAP) is often overexpressed in cancer cells, where it plays a key role in survival and also promotes invasiveness. To date however, the extracellular signals and intracellular pathways regulating its expression and activity remain incompletely understood. We have previously showed that exposure to each of the three TGF-β (transforming growth factor beta) isoforms upregulates XIAP protein content in endometrial carcinoma cells in vitro. In the present study, we have investigated the clinical relevance of TGF-β isoforms in endometrial tumours and the mechanisms through which TGF-β isoforms regulate XIAP content in uterine cancer cells.MethodsTGF-β isoforms immunoreactivity in clinical samples from endometrial tumours was assessed using immunofluorescence. Two model cancer cell lines (KLE endometrial carcinoma cells and HeLa cervical cancer cells) and pharmacological inhibitors were used to investigate the signalling pathways regulating XIAP expression and activity in response to autocrine and paracrine TGF-β in cancer cell.ResultsWe have found immunoreactivity for each TGF-β isoform in clinical samples from endometrial tumours, localizing to both stromal and epithelial/cancer cells. Blockade of autocrine TGF-β signaling in KLE endometrial carcinoma cells and HeLa cervical cancer cells reduced endogenous XIAP mRNA and protein levels. In addition, each TGF-β isoform upregulated XIAP gene expression when given exogenously, in a Smad/NF-κB dependent manner. This resulted in increased polyubiquitination of PTEN (phosphatase and tensin homolog on chromosome ten), a newly identified substrate for XIAP E3 ligase activity, and in a XIAP-dependent decrease of PTEN protein levels. Although each TGF-β isoform decreased PTEN content in a XIAP- and a Smad-dependent manner, decrease of PTEN levels in response to only one isoform, TGF-β3, was blocked by PI3-K inhibitor LY294002.ConclusionsXIAP gene expression and function is positively regulated by exposure to the three TGF-β isoforms in a Smad-dependent manner, similar to constitutive XIAP gene expression which depends on autocrine TGF-β/Smad signalling.

Ubiquitin-Proteasomal Degradation of COX-2 in TGF-β Stimulated Human Endometrial Cells Is Mediated Through Endoplasmic Reticulum Mannosidase I.

Cyclooxygenase (COX)-2 is a key regulatory enzyme in the production of prostaglandins (PG) during various physiological processes. Mechanisms of COX-2 regulation in human endometrial stromal cells (human endometrial stromal cells) are not fully understood. In this study, we investigate the role of TGF-β in the regulation of COX-2 in human uterine stromal cells. Each TGF-β isoform decreases COX-2 protein level in human uterine stromal cells in Smad2/3-dependent manner. The decrease in COX-2 is accompanied by a decrease in PG synthesis. Knockdown of Smad4 using specific small interfering RNA prevents the decrease in COX-2 protein, confirming that Smad pathway is implicated in the regulation of COX-2 expression in human endometrial stromal cells. Pretreatment with 26S proteasome inhibitor, MG132, significantly restores COX-2 protein and PG synthesis, indicating that COX-2 undergoes proteasomal degradation in the presence of TGF-β. In addition, each TGF-β isoform up-regulates endoplasmic reticulum (ER)-mannosidase I (ERManI) implying that COX-2 degradation is mediated through ER-associated degradation pathway in these cells. Furthermore, inhibition of ERManI activity using the mannosidase inhibitor (kifunensine), or small interfering RNA-mediated knockdown of ERManI, prevents TGF-β-induced COX-2 degradation. Taken together, these studies suggest that TGF-β promotes COX-2 degradation in a Smad-dependent manner by up-regulating the expression of ERManI and thereby enhancing ER-associated degradation and proteasomal degradation pathways.

Oxytocin Increases Invasive Properties of Endometrial Cancer Cells Through Phosphatidylinositol 3-Kinase/AKT-Dependent Up-Regulation of Cyclooxygenase-1, -2, and X-Linked Inhibitor of Apoptosis Protein

ABSTRACT Traditionally, oxytocin (OT) is well known to play a crucial role in the regulation of cyclic changes in the uterus, implantation of the embryo, and parturition. Recently, an additional role for OT has been identified in several types of cancer cells in which OT acts as a growth regulator. In endometrial cancer cells, OT is known to efficiently inhibit cellular proliferation. In the present study, we show that OT increases invasiveness of human endometrial carcinoma (HEC) cells, which are otherwise resistant to the growth-inhibiting effects of OT. Using pharmacological inhibitors, invasion assay, RNA interference, and immunofluorescence, we found that OT enhances the invasive properties of HEC cells through up-regulation of X-linked inhibitor of apoptosis protein (XIAP), matrix-metalloproteinase 2 (MMP2), and matrix-metalloproteinase 14 (MMP14). In addition, we show that OT-mediated invasion is both cyclooxygenase 1 (PTGS1) and cyclooxygenase-2 (PTGS2) dependent via the phosphatidylinositol 3-kinase/AKT (PIK3/AKT) pathway. PTGS2 knockdown by shRNA resulted in XIAP down-regulation. We also show that OT receptor is overexpressed in grade I to III endometrial cancer. Taken together, our results describe for the first time a novel role for OT in endometrial cancer cell invasion.

Primary cilia are present on human blood and bone marrow cells and mediate Hedgehog signaling

Primary cilia are nonmotile, microtubule-based organelles that are present on the cellular membrane of all eukaryotic cells. Functional cilia are required for the response to developmental signaling pathways such as Hedgehog (Hh) and Wnt/β-catenin. Although the Hh pathway has been shown to be active in leukemia and other blood cancers, there have been no reports describing the presence of primary cilia in human blood or leukemia cells. In the present study, we show that nearly all human blood and bone marrow cells have primary cilia (97-99%). In contrast, primary cilia on AML cell lines (KG1, KG1a, and K562) were less frequent (10-36% of cells) and were often shorter and dysmorphic, with less well-defined basal bodies. Finally, we show that treatment of blood cells with the Hh pathway ligand Sonic Hedgehog (SHh) causes translocation of Smoothened (SMO) to the primary cilia and activation of Hh target genes, demonstrating that primary cilia in blood cells are functional and participate in Hh signaling. Loss of primary cilia on leukemia cells may have important implications for aberrant pathway activation and response to SMO inhibitors currently in clinical development.